The invention relates to a method for the production of components such as, for example, gas turbine components, or of gear wheels, or of implants used in medical technology, which have a three-dimensionally formed surface. Further, the invention relates to a device for the production of components having a three-dimensionally formed surface.
Gas turbine rotors used in aircraft engineering increasingly are configured as integrally bladed rotors, in which case such integrally bladed rotors represent the rotor blades as an integral part of the rotor or a rotor base element. Such integrally bladed rotors are also referred to as a blisk (bladed disk) or as a bling (bladed ring), i.e., depending on whether a disk-shaped or a ring-shaped rotor base element is used. Integrally bladed gas turbine rotors consist of metal materials, in particular of materials that are difficult to machine such as titanium base alloys, nickel base alloys or cobalt base alloys. Referring to prior art, the production of three-dimensionally formed surfaces or aerodynamic structures on the rotor blades of such integrally bladed gas turbine rotors involves machining processes, such as, for example, milling processes. The production of three-dimensionally formed surfaces or aerodynamic structures on the rotor blades of integrally bladed rotors that consist of materials that are difficult to machine by means of milling processes is highly complex and extremely time-intensive, as well as cost-intensive. In addition, as a rule, subsequent finishing work is required.
The object of the present invention is to provide a novel method and a corresponding device for the production of components having a three-dimensionally formed surface.
In accordance with the invention, the method comprises the following steps: a) providing a specially pre-formed workpiece featuring a specific dimensional allowance; b) providing at least one working electrode, in which case the contour of the working electrode, or of each working electrode, is adapted to the contour of the three-dimensionally formed surface to be produced; c) lowering the three-dimensionally formed surface by placing the pre-formed workpiece and the working electrode, or each working electrode, in an electrolyte and by applying an electrical voltage or an electrical current, in which case the working electrode, or each working electrode, is moved in the sense of a circular advance motion in the direction toward the workpiece.
Referring to the present invention, a simple and quick option for the production of three-dimensionally formed surfaces or aerodynamic structures of workpieces is provided, the production being characterized by high precision and accuracy in the micrometer range. The surfaces or aerodynamic structures can be produced with such accuracy that subsequent processing becomes unnecessary.
Referring to an advantageous embodiment of the invention, the circular advance motion of the working electrode, or of each working electrode, in the direction toward the workpiece is superimposed by a pulsing or periodic movement in the direction of the advance motion, in order to expose gaps between the working electrode, or between each of the working electrodes, and the component for a forced rinsing of the gaps with electrolyte. Optionally, the circular advance motion of the working electrode, or of each working electrode, in the direction toward the workpiece can additionally be superimposed by a linear advance motion.
Preferably, the three-dimensionally formed surfaces produced with the inventive method are suction-side contours and pressure-side contours on the rotor blades of an integrally bladed rotor; whereby, in order to achieve this, an integrally bladed rotor of a rotor base element and rotor blades being integrally mounted to the base element and featuring a specific dimensional allowance are provided; whereby, in order to achieve this, furthermore, at least two working electrodes are provided for at least one rotor blade, a contour of one of the working electrodes being adapted to a contour of a suction-side contour to be created and a contour of the other working electrode being adapted to a contour of a pressure-side contour to be created; and whereby, in order to achieve this, furthermore, for the simultaneous lowering of the suction-side contour and the pressure-side contour in the region of at least one rotor blade, the corresponding working electrodes are moved in the sense of an opposite circular advance motion in the direction toward the respective rotor blade.
As a result of the option of making the aforementioned method a parallel operation, i.e., as a result of the simultaneous production of aerodynamic structures on several rotor blades, the processing time of integrally bladed rotors can be reduced, so that significant productivity increases can be achieved.